Power tool switch and speed control with control elements mounted in recesses in the tool handle

ABSTRACT

IN AN ELECTRICALLY DRIVEN APPLIANCE OF THE KIND COMPRISING A BODY SERVING AS A HOUSING FOR AN ELECTRIC DRIVING MOTOR AND AS A SUPPORT FOR A MEMBER DRIVEN BY THE MOTOR, AND A MANUALLY OPERABLE CONTROLS MEANS MOUNTED ON OR IN THE BODY FOR CONTROLLING OPERATION OF THE MOTOR, A COMPONENT PART OF THE BODY OF THE APPLIANCE IS FORMED AS AN ELECTRICALLY INSULATING   CASING IN WHICH INDIVIDUAL ELEMENTS OF SAID CONTROL MEANS ARE MOUNTED. THE COMPONENT PART MAY BE A HANDLE OF THE APPLIANCE AND THE ELEMENTS OF SAID CONTROL MEANS MAY INCLUDE ELEMENTS OF A SWITCH AND A DEVICE FOR CONTROLLING THE SPEED OF THE MOTOR OF THE APPLIANCE.

United States Patent zoo/155x zoo/157 x 318/345 31o/s0x 310/s0x zoo/157x 3 10/sox mLm mLL 3 in m mt: U O n maon n sabr ke w wm h. 03 ea flou GPSGBBBT 58777880 44666665 99999999 11111111 ll/l/l/l 496673 4 1 20632 86 889 4092 40789333 752227 0 J 22333332 d w c M-n m ml wmm 9 m m m r lkt fl uwnwunm EC7 -AH I de m N mm D .ln ng e emfl M pun-n5 l AFPA .1. 11.1.1] 2 253 7 2247 1. [1.1.1

541 rowan TOOL swrrcu AND SPEED CONTROL 'f' IN AS81818!" Exam mar-Robert A. Vanderhye RECESS IN THE TOOL HANDLE Attorney-Davis, Hoxie, F aithfull and Hapgood 3 Chile, 3 Drawing Figs.

ABSTRACT: In an electrically driven appliance of the kind 1 8 7 5% N M3 8 B .9 3 "3 L C S U 2 s 1.

comprising a body serving as a housing for an electric driving motor and as a support for a member driven by the motor, and a manually operable controls means mounted on or in the H0111 9/06, HOlh 13/08 [51] hit.

Field of 339/58;

body for controlling operation of the motor, a component part of the body of the appliance is formed as an electrically insu- 200/157; 310/50, 68.1; 318/345 (Cursory) lating casing in which individual elements of said control means are mounted. The component part may be a handle of the appliance and the elements of said control means may in- 200/157 clude elements of a switch and a device for controlling the 200/16 speed of the motor of the appliance.

[56] References Cited UNITED STATES PATENTS 3,072,768 l/l963 Happe et 3,225,149 12/1965 Shlesinger, Jr.

PATENTEU JUH28|9K1 sum 1 0r 3 I I l I l l l l. 4 l l EDGAR ALBERT PHILIP MITCOY IN VEN 70/? BY wa m. Honv. FAITHFULL 21 mmnon AUURNEY PATENIH] JUN 2 8191i sum 2 or 3 4a .IHl-

FIG. 2. f;

TDGAR T-LBFIRT PHILIP MILCOY PIOT TTT IN VENTUR TAITHY'I'LL POWER TOOL SWITCH AND SPEED CONTROL WITH CONTROL ELEMENTS MOUNTED IN RECESSES IN THE TOOL HANDLE This invention relates to an electrically driven portable appliance of the kind comprising a body serving as a housing for an electric driving motor and as a support for a member driven by the motor, and manually operable electric control means mounted on or in the body for controlling operation of the motor. Examples of such appliances are portable tools in which the driven member is a tool or tool holder, for example drilling machines, sanding machines, grinding machines, sawing machines and power screwdrivers. Other examples of such appliances are hair dryers and food mixers.

In use of a portable appliance of the kind referred to the body is held by the user and it is customary to form part of the body as a handle which can be grasped by the user. This handle may be formed integrally with the remainder of the body of the appliance or it may be removably secured to the latter.

The electric control means of a portable appliance of the kind referred to is usually either a simple on-off" switch or a combined switch and speed control device, for example an electronic speed control device. This control means is manufactured as a separate unit comprising an electrically insulating casing housing switch contacts or other circuit control elements, which casing is mounted in some part of the body of the portable appliance at the time of assembly of .the latter. Thus, it is common practice to mount a switch casing in a suitably shaped recess in the aforesaid handle, the switch usually being in the form of a trigger switch having its actuating trigger disposed in a convenient position for operation by a finger of a hand grasping the handle.

The separate production steps of assembling the parts of the electric control means and then subsequently mounting the assembled controlmeans in or on the body of the portable appliance represent significant items in the total cost of manufacturing the portable appliance.

One object of the present invention is to provide a method of manufacturing an electrically driven portable appliance of the kind referred to which is more economical thanhitherto known methods of manufacturing such portable appliances.

According to the invention a method of manufacturing an electrically driven portable appliance of the kind referred to, comprises the step of mounting individual elements of said control means in an electrically insulating casing which forms a part of the body of the portable appliance.

By assembling individual elements of said control means directly into a part of the body of the portable appliance a sig nificant saving is achieved in the total assembly time of the portable appliance.

According to a further aspect of the invention a component part of the body of an electrically driven appliance of the kind referred is formed as an electrically insulating casing in which individual elements of said control means are mounted.

In the case of a portable appliance in which the body thereof comprises one or more handles by means of which the appliance is held when in use, said component'part may form at least a part of the handle or one of the handles. For example, the handle may be formed in at least two parts adapted to be secured together with any suitable fixing means,-for example screws or rivets, these parts of the handle being shaped so that when assembled together they enclose the elements of said control means, for example switch contacts, in suitable recesses within the handle,. Such a handle may be removably secured to the remainder of the body of the appliance in any suitable way. The circuit control elements may be connected within the handle to one part of a separable electrical connector, for example a conventional plug and socket connector, the other part of which is mounted in the remainder of the body of the appliance. In this way, the electric control means is automatically connected into the electric circuit of the portable appliance when, during assembly of the handle on the remainder of the body of the appliance, the two halves of the connector are connected together.

The cable for supplying electricity to the portable-appliance may be led into the handle at any convenient point and the handle may incorporate conventional means for gripping the cable.

According to yet another aspect of the invention, in an electrically driven portable appliance of the kind referred to, the electric control means comprises an electrically insulating casing which houses circuit control elements, and said casing forms a part of the body of the portable appliance. Said casing, which may form at least part of a handle of theappliance, may be formed integrally with the remainder of the body of the appliance or it may be removably secured to the remainder of the body of the appliance.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which FIG. 1 is a schematic side view of one embodiment of a portable electrically driven appliance in accordance with the invention, the appliance illustrated being a portable drilling machine,

FIG. 2 is an enlarged end elevation of the handle of the appliance of FIG. 1,'viewed in the direction of the arrow A in F IG. 1, and

FIGS is a view taken on the line Ill-III of FIG. 2.

The portable drilling machine shown in FIG. 1 comprises a body, generally-indicated by the numeral 1, which includes a casing 2 and ahandle 3 which is removably secured to the casthe letter O.

The handle 3 (see FIGS. 2 and 3) is formed as a two-part casing of moulded electrically insulating material, the two handle parts 7a 7b being connected together by any suitable fixing means, for example screws 8. g

The handle part 70 serves as a base for the reception of circuit control elements for the motor M. These circuit control elements include a trigger switch, generally designated by the numeral 9, and a diode 10. The switch-9 comprises an actuating member 1 1 which is made of electrically insulating material and comprises a manually operable trigger lla joined to a slide b. The trigger 11a is received in a recess 12 in the bandle part 7a and the slide llb is received in a channel '13 forming an extension of the recess 12 in the handle part 7a. A helical spring 14 normally urges the actuating member 11 into the position shown in FIG. 3, in which a stop 15 on the trigger Ila bears against the end of a plunger 16 mounted in the handle part 7b (see FIG.2).

The slide 11b of the actuating member 11 supports two metallic bridging members 17, 18 which are received in slots 19, 20, respectively, disposed transversely with respect to the slide 11b.

The numerals 21 and 22 designate two metallic strip contacts mounted in grooves 23, 24 formed in the handle part 7a. Limbs 21a and 22a of these contacts are disposed in recesses 25,26, respectively in the handle part 7a and the bared conductors 27, 28 of a two-core cable 29 engage the contact limbs 21a, 22a within the recesses 25, 26. Flexible metallic strips 30, 31 housed in the recesses 25, 26, respectively, maintain the bared conductors 27, 28 in firm contact with the limbs 21a, 22a. The cable 29 is led into the handle part 7a through a bushing 32 and the cable is clamped in the handle part 7a by a conventional cable clamp 33.

The contacts 21, 22 comprise further limbs 21b and 22b, respectively, which are disposed flush with the vertical wall 13a of the channel 13.

Three other metallic strip contacts 3436 are mounted in grooves 37-39, respectively, in the hand part 7a. The contacts 34 and 35 comprise limbs 34a and 35a respectively, which are housed in a recess 40 in the handle part 7a. The

- disposed opposite the limb 21b of the contact 21.

The contact limb 35a and a limb 36a of the contact 36 extend into recesses 41, 42 respectively, in the handle part 7a. In these recesses the limbs 35a and 36a make electrical contact with bent flexible metallic strips 43, 44, respectively, which are housed in the recesses 41, 42, respectively. Prongs 45, 46 shown in chain lines in FIG. 3, enter the recesses 41, 42 respectively, through holes 47, 48, respectively, to make electrical contact with the strips 43, 44, respectively. The prongs 45, 46 are mounted on an electrically insulating support (not shown) in the casing 2 and are connected to leads (not shown) for conducting current to the motor M.

The contact 36 comprises a further limb 36b which is disposed flush with the vertical wall 13b of the channel 13 pposite to the limb 22b of contact 22.

When the trigger 11a is in the position shown in full lines in FIG. 3 there is no electrical connection between the cable 29 and the prongs 45,46 and the motor M is not energized.

If the trigger 11a is depressed into the recess 12 to the position indicated by the chain line H, the bridging member 17 makes contact with the contact limbs 21b and 34b and the bridging member 18 makes contact with the contact limbs 22b and 36b. This establishes a connection from the conductor 27 to the prong 45 via the contact 21, the bridging member 17, the contact 34, the diode 10, the contact limb 35a and the strip 43. A connection is also established from the conductor 28 to the prong 46 via the contact 22, the bridging member 18, the contact 36 and the strip 44. Current is thus supplies to the motor M in series with the diode and the motor M runs at a speed lower than full speed.

If the trigger 11a is depressed into the recess 12 to the position indicated by the chain line F, the bridging member 17 makes contact with the contact limbs 21b and 35b and the bridging member 18 makes contact with the contact limbs 22b and 36b. This establishes connections between the conductors 27, 28 and the prongs 45, 46, respectively, without the diode 10 in circuit and the motor M runs at full speed.

The plunger 16 may be adapted in known to lock the trigger lla in either of the positions H and F.

The handle part 7b serves as a cover for the handle part 7a and to retain the various parts of the switch 9 in their respective recesses, channel and grooves in the handle part 7a.

It is to be understood that the embodiment of the invention described with reference to the drawing may be modified in many ways within the scope of the invention as defined in the appended claims. Thus the handle 3 may form an integral part of the casing 2 and the circuit control elements for the motor M may take other forms than the switch 9 and diode 10. Again, the handle 3 may form part of a portable electrical appliance other than a drilling machine.

lclaim:

1. An insulating shell member comprising one exterior housing-part of a plural-part housing for a portable electrical appliance, in combination with a first wire terminal member for connection of a power conductor wire, said terminal member being mounted directly on and being held firmly within a first recess in said shell member by engagement with the walls thereof, fixed switch contact members mounted directly on and within a recess in said shell member, a switch operating member supported slidably within and guided by a recess in said shell member, a movable switch contact member carried by said switch operating member and movable to engage said fixed switch contact members, a third switch contact member within and held by the walls of a third recess in said shell member, said movable switch contact member when in one position engaging said first two fixed contact members and when in another position engaging one of said two fixed contact members and said third fixed co ntact member, solid state power-control means mounted within said shell member and connected to at least one of said fixed contact members for controlling the power delivery in one of said positions of said movable contact member, said movable contact member in the other of its said positions completing a connection for full power through said third fixed contact'member.

2. In the combination as claimed in claim 1, a pair of fixed contact members directly supported on and by the walls of recesses in said shell member, and a movable contact member carried by said switch operating member and engageable with said pair in both said one and said other positions of said firstmentioned movable contact member to complete a connection in a power line different from said first-mentioned fixed and movable contacts.

3. In the combination as claimed in claim 1, a pair of fixed contact members directly supported by said shell member and held within recesses in said shell member, movable contact member carried by said switch operating member and engageable with said pair in both said one and said other positions of said first-mentioned movable contact member to complete a connection in a power line different from said first-mentioned fixed and movable contacts, and a second wire terminal member mounted directly on said shell member for connection with an electric motor within said housing, said terminal members being integral with said one fixed contact member and with said third fixed contact member respectively. 

